This application proposes to develop a computer simulation of the critically ill patient, for use in training medical students, residents, nurses, fellows, and physicians. This computer software will faithfully simulate the functional aspects of cardiopulmonary physiology, using state-of-the-art mathematical models. For the first time, students at all levels will have the freedom to learn medical physiology and therapeutics by doing, rather than by watching. They will analyze, diagnose, and treat patients, by operating the simulator using patient scenario models that configure the system to simulate a patient with a specific critical illness (e.g., status asthmaticus, Adult Respiratory Distress Syndrome, Sepsis syndrome, etc.). By the end of Phase I, a functional simulator will be completed which simulates left and right heart dynamic performance, pulmonary gas exchange in a 50 compartment model of the lung, the systemic and pulmonary circulations including autonomic control and transvascular fluid balance, systemic gas exchange, and renal electrolyte and fluid exchange. Students will operate the simulator through a user-friendly graphical user interface operating under the Microsoft Windows environment. In Phase II, clinical case scenario modules will be added, along with a hypertext-type Help function. In addition, extensive testing will be carried out during Phase II. Virtually every English-speaking physician, surgeon, anesthesiologist, and student could benefit from this system, so the potential market is enormous.